Opus Genetics' Phentolamine Eye Drops Improve Dim-Light Vision in Phase III LYNX-1 Trial
核心洞察
Peer-reviewed LYNX-1 results show 21% of patients on 0.75% phentolamine drops gained at least three lines on a dim-light eye chart by day 15 versus 3% on placebo.
The once-nightly drop produces moderate pupil constriction lasting at least 20 hours by blocking iris dilator muscle (搜索) receptors without engaging the ciliary muscle.
The FDA has granted Fast Track designation for night driving impairment (搜索), while confirmatory LYNX-3 topline results are expected in the first half of 2026.
A once-nightly eye drop containing 0.75% phentolamine improved dim-light visual acuity in adults with night vision complaints, according to full peer-reviewed results from the Phase III LYNX-1 trial published online Sept. 2 in The American Journal of Ophthalmology. The drop, developed by Opus Genetics (formerly Ocuphire Pharma) with commercial partner Viatris, is not approved to treat night vision problems.
The multicenter trial enrolled 145 adults who reported glare, halos, or starbursts in low light and whose pupils widened to at least 5 millimeters in dim conditions. Participants were randomly assigned to phentolamine or placebo and used one drop in each eye every night for 14 days. The primary endpoint, measured on day 8, was a gain of 15 or more letters — three lines — on a dim, low-contrast eye chart.
LYNX-1 Efficacy Results
Thirteen percent of treated participants reached the primary vision goal at day 8, compared with 3% on placebo. By day 15, the treated share rose to 21%, while the placebo response remained at 3%. Patients also rated their overall night vision problems on a 1-to-7 scale, with 7 being most severe. Those treated with phentolamine scored 4.3 by day 8 and 3.3 after 15 days, versus 4.6 and 4.3 respectively in the placebo group — a statistically significant improvement. By day 15, treated participants also reported significantly less trouble with glare, halos, and starbursts than those on placebo.
A post-hoc analysis limited to the 25 participants who had undergone LASIK showed a stronger early response: 29% of treated participants reached the vision goal on day 8, compared with 9% on placebo, the company reported. The authors noted the subgroup was too small to support firm conclusions.
Mechanism and Safety Profile
Phentolamine works on the optics of the eye. Pupils widen at night, allowing light to pass through the outer edges of the cornea and lens, where irregularities scatter it into rings and streaks. The drug blocks receptors on the muscle that dilates the iris, keeping the pupil somewhat smaller in dim light. In the trial, that moderate pupil constriction lasted at least 20 hours.
The authors noted that the drug "does not engage the ciliary muscle," the focusing muscle inside the eye — distinguishing it from older pupil-shrinking drops that act on that muscle and can raise concerns about retinal tears or detachment in at-risk patients. Side effects in the trial were generally mild and short-lived.
Second Trial and Regulatory Status
Opus Genetics also reported encouraging initial results from a second Phase III trial, LYNX-2, which enrolled 199 people with reduced low-light, low-contrast vision after refractive procedures such as LASIK. In that study, 17.3% of treated patients reached the vision goal at day 15, compared with 9.2% on placebo, according to topline results released in 2025. Patients were treated and followed for six weeks, and Viatris said it saw no tachyphylaxis — a fading of effect with repeated use — over that period.
Dr. Jay Pepose, Opus Genetics' chief medical adviser and lead author of the LYNX-1 paper, said in a statement that in the second trial "we also saw functional improvements in difficulty of seeing the road because of oncoming headlights; and difficulty seeing due to glare when driving at dawn or dusk, as reported by patients in the trial." Pepose, of the Pepose Vision Institute in Chesterfield, Missouri, has pointed to the safety stakes, noting that some patients with poor low-light vision after refractive surgery "are more likely to be involved in motor vehicle collisions."
The U.S. Food and Drug Administration (搜索) has granted Fast Track designation for the eye drops as a treatment of significant chronic night driving impairment (搜索) after refractive surgery — a status given to drugs treating a serious condition or addressing an unmet medical need that can speed development and review. Opus said a confirmatory trial, LYNX-3, would report topline results in the first half of 2026, but the company's August financial update did not include them.
Phentolamine 0.75% is already marketed as Ryzumvi (搜索) to reverse pupil dilation after eye exams, but that approval does not cover night vision. The FDA has set an Oct. 17 decision date for the same drop as a presbyopia (搜索) treatment, according to Opus Genetics' annual corporate update. Approval for night vision problems would require confirmatory data and a separate FDA review.
Limitations of the Evidence
The LYNX-1 results were first presented at medical meetings in 2023; what is new is the full peer-reviewed publication. The trial did not measure driving performance, crash risk, or long-term safety. It was sponsored by the drug's developer, and several authors reported consulting ties to the company. Medscape's coverage of the paper described the difference between groups as fairly modest, with wide variation in who responded, and noted the study did not use standardized, validated vision questionnaires. Roughly four in five treated participants did not reach the main vision goal.
People most likely to notice glare and halos include those who have had LASIK, PRK, SMILE, or radial keratotomy; adults developing cataracts; and people with dry eye or an outdated glasses prescription. Many of those causes are treatable now, so a new or worsening night vision problem warrants an eye exam. Sudden changes — a new shower of floaters, flashes of light, a shadow or curtain over part of the vision, or halos with eye pain and nausea — can signal an emergency requiring same-day care. No price or insurance coverage has been set for night vision use, so out-of-pocket costs are unknown.